Epidemiology of IBD
Ulcerative Colitis Crohn’s Disease
Incidence (North America) per person-years 2.2–14.3:100,000 3.1–14.6:100,000
Age of onset 15–30 & 60–80 15–30 & 60–80
Ethnicity Jewish > non-Jewish white > African American > Hispanic > Asian
Male/female ratio 1:1 1.1–1.8:1
Smoking May prevent disease May cause disease
Oral contraceptives No increased risk Odds ratio 1.4
Appendectomy Protective Not protective
Monozygotic twins 6% concordance 58% concordance
Dizygotic twins 0% concordance 4% concordance